Hepatocyte growth factor is upregulated in ischemic retina and contributes to retinal vascular leakage and neovascularization

Obesity-related inflammatory protein signature in cardiovascular clinical outcomes: results from the Gutenberg Health Study

OBJECTIVE

The objective of this study was to investigate whether an obesity-related inflammatory protein signature (OIPS) is associated with adverse cardiovascular events.

METHODS

The Olink Target 96 Inflammation panel was performed in 6662 participants from the population-based Gutenberg Health Study (GHS). The OIPS was selected by a logistic regression model, and its association with cardiovascular outcomes was evaluated by Cox regression analysis. The GHS-derived OIPS was externally validated in the MyoVasc study.

RESULTS

The identified OIPS entailed 21 proteins involved in chemokine activity, tumor necrosis factor (TNF) receptor binding, and growth factor receptor binding. The signature revealed a novel positive association of axis inhibition protein 1 with obesity. The OIPS was associated with increased risk of all-cause and cardiac deaths, major adverse cardiovascular events, and incident coronary artery disease, independent of clinical covariates and established risk instruments. A BMI-stratified analysis confirmed the association of OIPS with increased death in those with obesity and overweight and with increased risk for coronary artery disease in those with obesity. The association of OIPS with increased risk of all-cause and cardiac deaths was validated in the MyoVasc cohort.

CONCLUSIONS

The OIPS showed a significant association with adverse clinical outcomes, particularly in those with overweight and obesity, and represents a promising tool for identifying patients at higher risk for worse cardiovascular outcomes.

Dual Pigment Epithelium-derived Factor and Hepatocyte Growth Factor Overexpression: A New Therapy for Pulmonary Hypertension

Pulmonary hypertension (PH) is a disease characterized by advanced pulmonary vasculature remodeling that is thought to be curable only through lung transplantation. The application of angiogenic hepatocyte growth factor (HGF) is reported to be protective in PH through its anti-vascular remodeling effect, but excessive HGF-mediated immature neovascularization is not conducive to the restoration of pulmonary perfusion because of apparent vascular leakage. As a canonical antiangiogenic molecule, pigment epithelium-derived factor (PEDF) inhibits angiogenesis and reduces vascular permeability in a variety of diseases. However, the effect of PEDF on HGF-based PH treatment remains to be determined. In this study, monocrotaline-induced PH rats and endothelial cells isolated from rat and human PH lung tissues were used. We assessed PH progression, right cardiac function, and pulmonary perfusion in HGF- and/or PEDF-treated rats with PH. Additionally, the receptor and mechanism responsible for the role of PEDF in HGF-based PH therapy were investigated. In this study, we found that HGF and PEDF jointly prevent PH development and improve right cardiac function in rats with PH. Moreover, PEDF delivery increases the pulmonary perfusion in PH lungs and inhibits immature angiogenesis and vascular endothelial (VE)-cadherin junction disintegration induced by HGF without affecting the therapeutic inhibition of pulmonary vascular remodeling by HGF. Mechanistically, PEDF targets VE growth factor receptor 2 and suppresses its phosphorylation at Y951 and Y1175 but not Y1214. Finally, VE growth factor receptor 2/VE protein tyrosine phosphatase/VE-cadherin complex formation and Akt and Erk1/2 inactivation were observed in rat and human PH lung endothelial cells. Collectively, our data indicate that PEDF additively enhances the efficacy of HGF against PH, which may provide new insights into treatment strategies for clinical PH.

Blocking the HGF-MET pathway induces resolution of neutrophilic inflammation by promoting neutrophil apoptosis and efferocytosis

Inflammation resolution is an active process that involves cellular events such as apoptosis and efferocytosis, which are key steps in the restoration of tissue homeostasis. Hepatocyte growth factor (HGF) is a growth factor mostly produced by mesenchymal-origin cells and has been described to act via MET receptor tyrosine kinase. The HGF/MET axis is essential for determining the progression and severity of inflammatory and immune-mediated disorders. Here, we investigated the effect of blocking the HGF/MET signalling pathway by PF-04217903 on the resolution of established models of neutrophilic inflammation. In a self-resolving model of gout induced by MSU crystals, HGF expression on periarticular tissue peaked at 12 h, the same time point that neutrophils reach their maximal accumulation in the joints. The HGF/MET axis was activated in this model, as demonstrated by increased levels of MET phosphorylation in neutrophils (Ly6G⁺ cells). In addition, the number of neutrophils was reduced in the knee exudate after PF-04217903 treatment, an effect accompanied by increased neutrophil apoptosis and efferocytosis and enhanced expression of Annexin A1, a key molecule for inflammation resolution. Reduced MPO activity, IL-1β and CXCL1 levels were also observed in periarticular tissue. Importantly, PF-04217903 reduced the histopathological score and hypernociceptive response. Similar findings were obtained in LPS-induced neutrophilic pleurisy. In human neutrophils, the combined use of LPS and HGF increased MET phosphorylation and provided a prosurvival signal, whereas blocking MET with PF-04217903 induced caspase-dependent neutrophil apoptosis. Taken together, these data demonstrate that blocking HGF/MET signalling may be a potential therapeutic strategy for inducing the resolution of neutrophilic inflammatory responses.

miR-145, miR-92a and miR-375 Show Differential Expression in Serum from Patients with Diabetic Retinopathies

Diabetic retinopathies are important disabling conditions. Micro-RNAs (miRNAs) are regulators of gene expression and diseases can change their expression. Our aim was to analyze the expression of miRNAs in serum and vitreous samples from patients with diabetic retinopathies. The following groups and number of individuals were included: proliferative diabetic retinopathy (PDR) (n = 16), diabetic macular edema (DME) (n = 17), and idiopathic epiretinal membrane (IEM) as non-diabetic controls (n = 23). The initial miRNA expression was explored using TaqMan low-density arrays (TLDAs) with subsequent validation through a quantitative polymerase chain reaction (qPCR). Target genes were identified through bioinformatic tools for enrichment analysis. The TLDAs revealed the following miRNAs with differential expression in terms of PDR vs. IEM: miR-320a-3p, miR-92a-3p, and miR-375-3p in the serum, with miR-541-5p and miR-223-5p in the vitreous samples. DME vs IEM: miR-486-5p, miR-145-5p, miR-197-3p, and miR-125b-5p in the serum, and miR-212-3p in vitreous samples. PDR vs. DME: miR-486-5p, miR-100-5p, miR-328-3p, miR-660-5p, and miR-145 in the serum and none in the vitreous samples. Validation was confirmed only for miR-145, miR-92a, and miR-375 in the serum. The relevant enriched pathways for these three validated miRNAs, miR-145, miR-92a, and miR-375 were the vascular endothelial growth factor and its receptor, hepatocyte growth factor receptor, epidermal growth factor, focal adhesion, and phosphoinositide 3-kinase. Our results support the involvement of miRNAs in the pathophysiology of diabetic retinopathies and reinforce their potential as biomarkers or therapeutic resources.

Endothelial dysfunction contributes to severe COVID-19 in combination with dysregulated lymphocyte responses and cytokine networks

The systemic processes involved in the manifestation of life-threatening COVID-19 and in disease recovery are still incompletely understood, despite investigations focusing on the dysregulation of immune responses after SARS-CoV-2 infection. To define hallmarks of severe COVID-19 in acute disease (n = 58) and in disease recovery in convalescent patients (n = 28) from Hannover Medical School, we used flow cytometry and proteomics data with unsupervised clustering analyses. In our observational study, we combined analyses of immune cells and cytokine/chemokine networks with endothelial activation and injury. ICU patients displayed an altered immune signature with prolonged lymphopenia but the expansion of granulocytes and plasmablasts along with activated and terminally differentiated T and NK cells and high levels of SARS-CoV-2-specific antibodies. The core signature of seven plasma proteins revealed a highly inflammatory microenvironment in addition to endothelial injury in severe COVID-19. Changes within this signature were associated with either disease progression or recovery. In summary, our data suggest that besides a strong inflammatory response, severe COVID-19 is driven by endothelial activation and barrier disruption, whereby recovery depends on the regeneration of the endothelial integrity.

Thioredoxin Delays Photoreceptor Degeneration, Oxidative and Inflammation Alterations in Retinitis Pigmentosa

Retinitis pigmentosa (RP) is an inherited ocular disorder with no effective treatment. RP onset and progression trigger a cascade of retinal disorders that lead to the death of photoreceptors. After photoreceptors death, neuronal, glial and vascular remodeling can be observed in the retina. The purpose of this study was to study if thioredoxin (TRX) administration is able to decrease photoreceptor death in an animal model of RP (rd1 mouse), but also if it is able to modulate the retinal oxidative stress, glial and vascular changes that can be observed as the disease progresses. Wild type and rd1 mice received several doses of TRX. After treatment, animals were euthanized at postnatals days 11, 17, or 28. Glutathione (GSH) and other thiol compounds were determined by high performance liquid chromatography (HPLC). Glial fibrilary acidic protein (GFAP) and anti-ionized calcium binding adaptor molecule 1 (Iba1) were studied by immunohistochemistry. Vascular endothelial growth factor (VEGF) and hepatic growth factor (HGF) expression were determined by western blot. TRX administration significantly diminished cell death in rd1 mouse retinas and increased GSH retinal concentrations at postnatal day 11 (PN11). TRX was also able to reverse glial alterations at PN11 and PN17. No alterations were observed in retinal VEGF and HGF expression in rd1 mice. In conclusion, TRX treatment decreases photoreceptor death in the first stages of RP and this protective effect may be due in part to the GSH system activation and to a partially decrease in inflammation.

Hepatocyte growth factor prevents pericyte loss in diabetic retinopathy

Diabetic retinopathy (DR) is a disease that causes blindness due to vascular leakage or abnormal angiogenesis. Hepatocyte growth factor (HGF) is increased in the serum or vitreous fluid in proliferative diabetic retinopathy (PDR) patients, although the effect of HGF on the blood vessels remains unclear. This study focused on the effect of HGF on pericyte (PC) survival and endothelial cell (EC) permeability. It was demonstrated that HGF was increased in the diabetic mouse retina. However, HGF prevented PC apoptosis caused by TNF-α, which increased in the diabetic retinas both in vitro and in vivo. In addition, HGF was involved in PC survival by increasing the Akt signaling pathway. Moreover, HGF strengthened the EC tight junction in co-cultures of PCs and ECs by promoting PC survival, thereby reducing EC permeability. These results suggest that HGF may play a role in the prevention of increased vascular leakage by inhibiting the PC loss that occurs in DR to some extent. However, careful HGF reduction in DR might avoid an increase in PC loss.

Sustained suppression of VEGF for treatment of retinal/choroidal vascular diseases

Neovascular age-related macular degeneration (NVAMD) is the most prevalent choroidal vascular disease, and diabetic retinopathy (DR) and retinal vein occlusion (RVO) are the most prevalent retinal vascular diseases. In each of these, hypoxia plays a central role by stabilizing hypoxia-inducible factor-1 which increases production of vascular endothelial growth factor (VEGF) and other hypoxia-regulated gene products. High VEGF causes excessive vascular permeability, neovascularization, and in DR and RVO, promotes closure of retinal vessels exacerbating hypoxia and creating a positive feedback loop. Hence once VEGF expression is elevated it tends to remain elevated and drives disease progression. While other hypoxia-regulated gene products also contribute to pathology in these disease processes, it is remarkable how much pathology is reversed by selective inhibition of VEGF. Clinical trials have demonstrated outstanding visual outcomes in patients with NVAMD, DR, or RVO from frequent intraocular injections of VEGF-neutralizing proteins, but for a variety of reasons injection frequency has been substantially less in clinical practice and visual outcomes are disappointing. Herein we discuss the rationale, preclinical, and early clinical results of new approaches that provide sustained suppression of VEGF. These approaches will revolutionize the management of these prevalent retinal/choroidal vascular diseases.